Switch



Dec. 9, 1958 w. w. CARDIN Erm.

SWITCH Filed May 22, 1956 mi w Mum M J n da mm .d Jw. u Ww 6 H Dec. 9, 1958 W- W- CARDIN ET AL 2,863,965

SWITCH Filed May 22, 1956 5 Sheets-Sheet 2 ll/M fg. y.

Wilfred W Cardin Heiz@ az/z'd Epstein, ty w. m9.

Dec. 9, 1958 w. w. CARDIN Erm. 2,863,965

SWITCH Filed May 22, 1956 3 Sheets-Sheet 3 United States Patent@ SWITCH "Y:

Wilfred 4W.Cairdin, Attleboro, andrHenry David-Epstein,

Boston, 1Mass.,fassign ors toy Metals 5& Controls Corpo- Y ration, Attleboro, Mass.,:a corporation of Massachusetts This' invention relates 1 to thermostaticswitches;fand* more particularly,V toA thermostaticf switches which are" controllable ,manually lin conjunction with' Vthe'rrnostati'c y control thereof.

This "invention represents an-A improvement Aover' the invention' disclosedandl claimed in UnitedStates letters,` Patent 2,345,451; Vgrantedv March f28;=l944,^'-to"]. D.- Bo'lesky'." In additionfto'the advantages provid'ed by the invention-setV forth in that patent; the present invention provides additional advantages thereover ands 'obvia-tes" certain4 disadvantages thereof as will v'becomeapparentf as 'theV description proceeds.;`

Accordingly, an objectlfof the presentf invention-is "tol` provide a thermostatic-'switch' which-provides the advan-"i tages Vset -forth in-theabovementioned YpatentV and,

addition, which Y represents' Vvan improvement over Vthe pin-ijq 30 ventionpresented thereby.`

A Jfurtherobject 'of lthisinvention is to'fprovidea thermostat-ic switch having improved' translation of'forces y35 thermostatic switchby' which 'localized-1.deformation 'of the: thermostatic means is substantially eliminated/or-l to the thermostatio-means. i

A further-objectof `this invention is to=-provide`a greatly reduced.-

A further object of vtheinvention is to provide athermo-A i static switch-which is morel easily and morel accurately."

calibrated.

A further objectv offthis invention fis toiprovidefan improved thermostatio switch embodyingithermostaticr means upon which'wear'is substantially reduceditherebyf prolongingthel useful'life of the switch-5f alter. thel movementof the.,contactsnthereof'zto `closed position.

Other objects will bein part -obvious'andrin part pointed outy hereinafter.

T he'invention accordingly comprises theelements-fandw combination of elements, features of constructiomand` arrangement of parts lwhich will be `exemplified in the structureshereinafter described,'-fand the-scopeof the;u

application of which will be indicated in theollowing" claims.

In the accompanying drawings, in which are` illustratedv several of various possible embodiments of theinvention,

Fig. l is a plan view' of a switchY embodying the present invention;

Fig; 2 is a sectionalrview taken along lin'eHZ-'Z inV Fig. .3 is a sectional` view taken along line. 3-3 inn Fig. v4 is fa view similar to Figll but Ywith the' cover] and actuating means removed;

ice

Z. Fig.` 5 is a view sirriilarto'Fi'g.` 2 but'shownglthepa'r'tsf in "a l diier'ent "positiong' Fig. 6 is a broken view/,partlyin'section,y `and"sh`ojwir'1'g"y a portionof an actuating means of dile'rent forni"'tltaiify that shown in'FigsgZ and 5;

Figi." y12`is a f-ragment'ay'side view including 'a thermo' static subassembly of "different ',formthan that included' in Figs. 2 and 7 andFi'g. 115 and-` l Fig'. l3is a fragmentary view Isimilar to a portion/of Figw'/ But showing' thefthermostatie elementin a'- diierenty position u Similar :referencey numerals indicate like parts thugl'r-Y outthe several viewsofL-thedrawings. A

Referring toA` Figs: 5,- lwhich illustrate A`'oneembodilf ment of this' inve'ntion,`-'a baise or^casing`2 is 'shovv'irwhiclr' is lformed Vofa suitablefinsul'ating material-suchjas one ofthe' customary'molded plastics, 'ceramics,` etc. Bas'eZ i includes a lower -ba's'e member4 andi an-lupper base mem berf'orf-coverff6. l: Base fr'ne'mbejr'4 includes side-"walls 8,-z 8 and'lend fwalls`10,"10,all^ of -which 'mate with-V base? member-6. FiXedlyc'arriedby' base member=4 a'reielecf trica'lly conductive' terminals U12 and 14`,f Veach lof" which 'f includes-fa laterally extending `po`rtion 16-l and 18,1resp'e`c-i tivelyw4 Portion-16' of terminal lzrnoun't's an"electrical i contact 20, fand portionfh18- of terminal 514V mounts'i an# electrical 1VContact 22.1.

Baseirnen'rberl4 providesa raised? b'o`s`s'1-24havingf-a socket: 26 therein.- 1 A bushingizsmaylb'e fixedly seeu'redif'L in Isocket' 26 asfshownlin Figs. 2 and 5.

A thermostatic sub-assembly 2'9fis 'forrried,\inpartyb y"Y thermostatic elementi l *30; Thermostatic 'l le'me'nt" 30! iis electrically#y conductive' 'and "snap'cting'in response to '-3 temperaturechange Thislelement-imay fbei of lthef-t if disclosedi-nUnited-StatesV Letters Patents 1,448,240 2,317,831, or Vdisclosed in 'copendingapplicationllSeriall No.1 14973109,-lledMarcht-ZS,y i955 I yRefereiJrcef-is herebyLf madeito these disclosuresfor the' details of ystructure and-\ function'f'of this type4 oflftherm'o'static'element. l

An electrical contactlEaZ-lis carried byf'thermostatic-J element 'Mlfory cooperation with Contact 20 fThe'rmostatic element-.30 maylcarry'another contact 34lfor coopera?! tion lwith contact-22. '-It will-bejclear that one1'of1co11-1` tacts 32. or'34 could*-befeliminated dependingfupon the?? intendedl-functionsof the-switch .For example, aniin-iii sulating-piece Vcould Vbe substituted for 'either ofcontactsf;` 32` or; 34a* Alternatively;y -thermostaticl'element 302 could i. beprovidedwith additional contacts;

An aperture 35iis provided Vin thermostatic'elementf'f whichl extends therethrough -Ifrom lone Sside to the other. Asfbestshown in Figs. -2 andl 5, a shankv36is looselyadis'el? posed in aperture 3521 `Provided on shank .36;-is `aV head1 suitable'rnanner such as by staking at 44;. Cup-shaped; l.member 42 `is `telescopically engaged with and guidedfor movement with respect to baseZ by bushing 28;"A Means for biasing thermostatic element 30 upwardly as viewed in Figs. 2 and 5 is provided in the form of a compression coil spring 46 having one end engaged with base 2 and its other end seated in cup-shapedmernber 42. Cornpresson spring 46 biases thermostatic element 30 for movement along a path from the position with respect to contacts 20 and 22 as shown in Fig. 2 to the relative position shown in Fig. 5. It will be noted that with thermostatic element 30 in the downwardly bowed shape or condition shown in Fig. 2 and with the parts in the position shown in Fig. 2, contact 32 engages its cooperating contact 20, and contact 34 engages its cooperating contact 22. By means later to be described, thermostatic sub-assembly 29, which includes shank 36, head 38, thermostatic element 30 and cup-shaped member 42, may be forcibly disposed in the position shown in Fig. 2 and may be released by said means to permit movement of thermostat sub-assembly 29 to the position shown in Fig. 5. Substantial rotation of thermostatic element 30 about shank 36 is prevented by engagement of the distal portions of element 3i) with the respective, relative adjacent surfaces of base member 4.

Base member or cover member 6 includes end walls 50, 50 and side walls 52, 52 which intert with end walls 10, 10 and side walls 8, 8, respectively, of base member 4. Base members 4 and 6 may be secured together by conventional means such as headed screws 55. End walls 50, 50 provide overhanging portions 54, 54, respectively, for a purpose later to become apparent.

Movable means are carried by cover member 6 for cooperation with thermostatic sub-assembly 29 to effect movement of thermostatic element 30 between the respective positions shown in Figs. 2 and 5. An aperture 56 is provided in cover member 6 through which the handle 58 of this movable means projects outwardly to the exterior of the device. Handle 58 is integral with and forms a portion of movable supporting member 60. Supporting member 60 is mounted on base member 6 for pivotal movement about an axis by means of axially extending bearing portions 62 and 64 which are slidably mounted in cylindrical apertures 66 and 68, respectively. As best shown in Fig. 3, the surfaces of cylindrical apertures 66 and 68 act as bearing suports for the portions of the sup porting member disposed therein.

Supporting member 60 provides an internally threaded aperture 70 which preferably is substantially aligned or coaxial with cup-shaped member 42 when the parts are in the relative position shown in Fig. 2. An externally threaded member, in this case an adjusting screw 72, is threaded into aperture 70. At one end of adjusting screw 72 is a cam 76 which cooperates with cam 39 and catch 40 when supporting means 60 is pivoted from the position shown in Fig. 5 to that shown in Fig. 2. It is apparent that adjusting screw 72 is adjustable along aperture 70 by merely rotating member 72 relative to support 60. Means such as a screw driver may be inserted through aperture 56 and into engagement with slot 78 in adjusting screw 72 for rotating it relative to supporting means 60. In this manner, adjusting screw 72 is accessible from the exterior of the device for adjustment of this member along support 60 and transversely with respect to the axis about which support 60 pivots.

Supporting means 60 provides a socket 82 in which one end of a compression coil spring 84 is seated. The opposite end of coil spring 84 is seated in a socket 86 provided by cover member 6. Coil spring 84 resiliently biases supporting member 60 for movement from the relative position shown in Fig. 2 to the retracted position shown in Fig. 5.

In operation, supporting means 60 may be disposed in the fully counterclockwise position shown in Fig. 5, which position is defined by engagement of handle 58 with the relatively adjacent portion of cover member 6. Durshown in Fig. 5 to the postion shown in Fig. 2, cam 76 at the end of member 72 moves into engagement with cooperating cam 39 provided by head 38. Continued movement of supporting member 60 in the clockwise direction is effective to move thermostatic sub-assembly 29 downwardly to the reset position shown in Fig. 2. At the position shown in Fig. 2, cam 76 has moved past cam 39 and into engagement with the catch folmed by depression 40. Preferably, thermostatic element 30 is liexed by the pressure of cam 76 against head 38 when-in the position shown in Fig. 2 to effect adjustment of element 30 as is well-known in the art, whereby creep of contacts 32 and 34 vmay be eliminated, and the desired operating temperature of the element is set. Although thermostatic element 3l) is biased upwardly due to this mechanical flexure and by coil spring 46, and although supporting member 60 is biased in the counterclockwise direction by spring 84, the shape and arrangement of cam 76 and depression 40 is such that the parts will maintain themselves in the position shown in Fig. 2. In this position the contacts are closed. The contacts may be opened manually by simply moving handle 58 forcibly in a counterclockwise direction as viewed in Fig. 2 to the retracted position shown in Fig. 5 whereby sub-assembly 29, which includes thermostatic element 30, moves upwardly under the bias of element 30 and spring 46 to the position shown in Fig. 5 at which the contacts are mutually separated. Alternatively, with the parts in the position shown in Fig. 2, thermostatic element 30 is responsive to temperature change, such as that which might be occasioned by a current overload passing through element 30, whereby thermostatic element 30 would snap from the downwardly bowed shape or condition shown in Fig. 2 to an upwardly bowed shape or condition at which contacts 32 and 34 would be biased in a direction from engaged to disengaged relation with contacts 20 and 22, respectively. The result of this bias in the environment shown in Figs. 1-5 is that contacts 32 and 34 will be disengaged from contacts 20 and 22, respectively. At the point of snap of thermostatic element 30 from the downwardly bowed to the upwardly bowed shape, the upward bias of thermostatic element 30 due to the mechanical ilexure thereof is released whereby catch 40 releases cam 76 and spring 84 is effective to pivot supporting member 60 in the counterclockwise direction as viewed in Fig. 2. Cam 76 having pivoted away from head 38, thermostatic sub-assembly 29 moves up wardly in its upwardly bowed shape or condition to the relative position shown in Fig. 5. With sub-assembly 29 in the position shown in Fig. 5 and with element 30 in its upwardly bowed condition, over-hanging portions 54, 54 engage the distal portions of elementk 30 and thereby act as stops to limit upward movement of these distal portions.

After thermostatic element 30 snaps from the shape or condition shown in Figs. 2 and 5 to the above-described upwardly bowed shape or condition, contacts 32 and 34 will be mutually separated from contacts 20 and 22, respectively, in the environment shown in Figs. l-5, regardless of the pivotal position of supporting member 60. That is, even if supporting member 60 were pivoted from the position shown in Fig. 5 to that shown in Fig. 2 while the thermostatic element was in its upwardly bowed shape or condition (as indicated by the dotted-line shape of thermostatic element 30 in Fig. 2), neither of contacts 32 nor 34 would move into engagement with its respective cooperating contact. However, although contacts 32 and 34 (with supporting member 60 in its fully clockwise position as shown in Fig. 2) will be separated from their respective cooperating contacts when thermostatic element 30 has snapped to said upwardly bowed shape, contacts 32 and 34 will be engaged with their respective cooperating contacts when supporting member 60 is in its fully clockwise position and thermostatic element 30 has snapped from the abovedescribed, upwardly bowed condition to the downwardly bowed shape or condition shown in full lines in Fig. 2.

Accordingly, thermostatic element 30 along with the other parts of sub-assembly 29, is biased for movement along a path from a first position to a second position with respect to contacts 20 and 22 whereby in said rst position the thermostatic means, when it responds to temperature change to change its shape, biases contacts 32 and 34 in a direction from-engaging to disengaging position withrespect to contacts 20 and 22, respectively. It

will be noted that this embodiment and the embodiment shown in Figs. 7-10, whether or not modified as described herein, are trip-free. That is, even if handle 58 should be held in the position shown in Fig. 2, the snap of the thermostatic element in response to temperature change from its downwardly bowed condition to its upwardly Abowed condition is effective to separate contacts 32 and 34 from contacts 20 and 22, respectively. Also, it will be noted thatl each of contacts 32 and 34 is disengaged from contacts, 20 and 22, respectively, when thermostatic element 30 is disposed in the position and environment shown in Fig. 5 regardless of whether thermostatic element 30 is in the downwardly bowed shape or condition shown in Figs. 2 and 5 or in the upwardly bowed shape or condition described above.

It will be clear that the extent of movement of thermo,- static element 30, as well as the amount of pull-in of thermostatic element 30, eected by pivotal movement of the supporting member from the position shown in Fig. 5 to that shown in Fig. 2 is determined by the adjustment of member 72 transversely of the pivotal axis of supporting member 60 Vand along supporting member 60. With supporting member 60 in the position shown in Fig. 2, the adjustable position of member 72 can be quickly, easily and accurately set.

Fig. 6 shows a member 90 which may be substituted for member 72 in the embodiment shown in Figs. 1-5. Member 90 may be substantially identical with member 72 except for the end thereof which provides the cam means for cooperation with cam 39 and depressie-n 40. In this regard member 90 lprovides at one end a socket 92 which receives a cam in the form of a spherical ball 94.- Ball 94 may be retained in socket 92 by spinning or otherwise turning in the end of member 92 at 96 in such manner -that the ball can rotate freely.

Referring to the embodiment shown in Figs. 7-10 and 13, a base or casing 100 is shown which includes an openended base member 101. Base member 101 is hollow andY provides internal surfaces closely tting the subassembly 102 shown in Fig. l0. Subassembly 102 includes two electrically conductive terminals 104 and 106 which closely interfit with apertures 105 and 107, respectively, in base member 101 and which mount electrical contacts 108 and 110, respectively. Terminals 104 and 106 are xedly secured to a base member 112 in any suitable manner. Base member 112 is formed of a suitable electrically insulating material and provides a boss 113 having socket 114 therein in which a bushing 116 is xedly mounted.

A thermostatic sub-assembly 118,which is or may be identical with thermostatic sub-assembly 29 as described with respect to the embodiment shown in Figs. l through 5, is mounted for movement with respect to base member 112 in the same manner as sub-assembly 29 is mounted for movement with respect to base member 4. That is, head 120, shank 122, thermostatic element 124, and cup-shaped member 126 may be of the same form and construction as the corresponding parts in the embodiment shown in Figs. 1-5; and cup-shaped member 126 may4 be mounted telescopically in bushing 116 and confined for movement therein. Substantial rotation of thermostatic element` 124 about shank 122 is prevented by .engagement of the distal portions of element 124 with the respective, relatively adjacent surfaces 127, 127 of base member 112. Electrical contacts 128 and 130 are carried by thermostatic element 124 for cooperating with contacts 108and 110, respectively. A compression coil spring 132 has one end disposed against base member 112 and the Aother end seated in cup-shaped member 126 to resiliently bias subassembly 118 upwardly as viewed in Figs. 7 and 8. Head provides a cam surface 136 and a `catch 138 in the same manner as that provided by head 38-in the previously-described embodiment.

The open end of base member 101 may be substantially closed by a closure member 140. Member may be secured to base member 101 by means such as screws 142. Slidably .mounted in an aperture 144 in member 140 is a manually engageable, push-pull member 146. One leg 148, of a supporting means 149 in thev form lof. an L-shaped member, is interlocked with a projection 150 secured to member 146. The other leg 152 vofL-shaped member 149 is disposed in slidable, interftting relationship with a substantially straight guideway provided` by recesses 153, 153 in base member 101. Accordingly, member 146 and legs 152 and 148 are mounted for rectilinear movement on and with respect to base 100.

ber 156, or its substitute as the 'case may be, positively.

to lock that member rotationally with respect to leg 152. An aperture is provided by base member 101 such that with the parts in the position shown in Fig. 7, lock nut 159 and member 154 are accessible from the exterior of the device. Accordingly, the position of member 156 with respect to leg 152 may be adjusted thereby to adjust member 156 along leg 152 and transverselyV of the path of rectilinear movement of leg 152.

A coiled compression spring 162 has one end seated in a socket 164 provided by base member 101 and has its other end disposed against the relatively adjacent end of leg 152. Spring 162 resiliently biases leg 152V and the structure tixed with respect thereto, for movement from the position shown in Fig. 7 to the retractedposition shown in Fig. 8.

Fixed with respect to closure member 140 is an externally threaded portion 166. Figs. 7 and 8 illustrate the manner in which the switch may be mountedwith portion 166 disposed in an aperture 168 in a panel or partition 170. In this regard, a nut 172 in threaded engagement with portion 166 may be disposed against one side.

of panel 170, and a lock nut 174 may be tightened down in threaded engagement with portion 166 and against the other side of panel 170.

In operation, member 146 is manually engageable and movable to the position shown in Fig. 7. During this movement cam 158 moves into engagement with cam 136 to move thermostatic sub-assembly 118 toward con-I tacts 108 and 110. This movement brings contacts 128 and 130 into engagement with contacts 108 and 110, respectively, and continued movement of member 146 is effective to dispose cam 158 in catch 138 as shown in Fig. 7. In the position shown in Fig. 7 sub-assembly 118 is resiliently urged in a direction away from contactsV 108 and 110 due to the mechanical flexure of thermostatic element 124 and due to compression spring 132. Leg 152 is resiliently urged to the right as viewed in Fig. 7 by compression spring 162. However, the shape and relative arrangement of cam 158 and catch 138 are such as to maintain the-parts in they position shown in Fig.Y

' to the other.

7. L-shaped' member 14S! 'can be forcibly retracted to the position shown in Fig. 8 whereby cam 158 will be released from catch 138 to permit thermostatic sub-assembly 118 to move from the position shown in Fig. 7 to the position shown in Fig. 8 under the bias of element 124. and spring 132. Also, thermostatic element 124 is snappable, in response to temperature change, from the. downwardly bowed shape or condition shown in Figs. 7 and 8 to an upwardly bowed shape or condition as described with respect to the Figs. 15 embodiment. When thermostatic element 124 snaps to this upwardly bowed condition, thermostatic element 124 resiliently biases contacts 128 and 130 in a direction away from contacts'108 and 110, respectively, and the resilient bias due to mechanical flexure of the thermostatic element is released permitting cam 158 to be released `from catch 138. When cam 158 is released from catch 138, L-shaped member 1494 moves .to the` retracted position shown in Fig. 8 under the biasof compression spring 162. As with the embodiment shown in Figs. 145, when thermostatic element 124 is in the position shown in Fig. 7, contacts 128 and 130 will be in engagement with contacts 108 and 110, respectively, so long as the thermostatic element remains in the downwardly bowed shape or condition shown in Figs. 7 and 8. However, and as clearly illustrated in Fig. 13, when thermostatic element 124 is in the above-described upwardly bowed shape or condition and in the environment shown in Figs. 79 and 13, contacts 128 and 130 will remain out of engagement with contacts 108 and 110 regardless of whether the thermostatic sub-assembly is in the position shown in Fig. 7 or the position shown in Fig. 8. Accordingly, referring to Fig. 13 it will be apparent that with the parts in the environment shown in Figs. 79 and after thermostatic element 124 hasy snapped to the upwardly bowed' condition in response to a temperature change, contacts 128 and 130 will remain out of engagement with contacts 108 and 110 even though supporting member 1'49 has moved to the position shown in Fig. 7.

Upstanding portions 178 and 180 may be provided in xed relation to base member 112 as shown in Figs. 7, 8 and 10. Portions 178 and.180 are preferably integral with base 112 and are also formed of electrically insulating material. These portions act as barriers to prevent the possibility Iof 'an arc occurring between thermostatic element 124 and either of contacts 108 and 110.

Fig. 11 illustrates a portion of a modified form of thermostatic.sub-assembly which may be substituted for that shown in both of the above-described embodiments. For the purposes of this description, this modified subassembly has been shown in Fig. 11 as having beenl incorporated into the embodiment of Figs; 7-10. Accord-` ing to this modiiied form, thermostatic sub-assembly 181 includes a thermostatic element 182 which is or may be identical with the thermostatic element included in both;

of the above-described embodiments. In this regard thermostatic element 182 provides an aperture 184 located substantially centrally thereof and extending through thermostatic element 182 from one side thereof Thermostatic sub-assembly 181 further includesY a shank 186v disposed in aperture 184 and extending within bushing 116. A c-ompression coil spring 188 is disposed about shank 186 and within bushing 116. Oneend of coil spring 188 is disposed against base member 101 and the other end thereof is disposed against one side of thermostatic element 182. A headv 190 is lixedly carriedk by shank 186. The lower portion of head 190 is engageable with the side of thermostatic element 132 opposite fro-m that engaged by one end of spring 188. Another portion of head 190 provides a cam surface 192 for cooperation with cam 158 and socket -or catch 194. Bushing 116, in cooperation with spring 188 and shank 186, guides thermostatic element 182 in its path of movement between the above-described relative positions. It will be apparent that thermostatic sub-as- 8 sembl'y 181 functionsv in substantially the 'sar'ne manner and provides substantially the same advantages as that attributed above with respect to the thermostatic subassembly incorporated in the embodiments shown in Figs. l-S'and 7-10.

In Fig. 12, another thermostatic sub-assembly 200 is shown which may vbe substituted for thermostatic subassembly 29 in the embodiment shown in Figs. 1-5. Thermostatic sub-assembly 200 includes a thermostatic element 202 which is or may be identical with the thermostatic element included in both of the above-described embodiments. In this regard thermostatic element 200 provides an aperture 204 located substantially centrally thereof and extending through this` element fromv onel side thereof to the other. Thermostatic sub-assemblyy 200 further includes a generally cup-shaped member 2.06.

Integral with cup-shaped member 206 or otherwise se cured thereto, is a member 207 which provides a shankV 208 extending between shoulder 209 and flange 210. AsV

is apparent from Fig. 12, shank 208 is disposed within aperture 204 provided by thermostatic element 202, the latter being carried onl the member 207 between the said flanges. Alternatively, it will be obvious that thermostatic element 202 may be mounted in like manner on member 207 between flange 210 and the adjacent portion of cup-shaped member 206. A-shank 212 ixedly carries` a head 214. Head 214 provides a cam or cam surface 216 and a catch 218. Shank 212 threadedly engages a complementary threaded aperture 220 in cup-shaped member 206 and member 207-. Cup-shaped member 206 is slidably` received in and guided lfor movement by bushing 28 which is iixedly supported `by base member 4'. Thermostatic sub-assembly 200 is biased upwardly as viewed in Fig. l2 by spring 46. 'It will be noted that base member 4', as shown in Fig. 12, is or maybe.

substantially identical with base member 4 as shown in Fig. 5 except that in the modification shown in Fig. 12, an aperture 222 is provided in base membery 4 in substantial alignment with threaded shank 212. It will be seen that threaded shank 212 is accessible from the eX- terior of the device whereby a tool such as a screw driver may be inserted through aperture 222 to engage a slot 224. ln this manner head 214 is adjustable along its supporting means and transversely with respect to the axis about which support 60 of this embodiment pivots. By this means the extent of movement of the thermostatic sub-assembly from the position shown in Fig. 5 to the position shown in Fig. 2, and, concomitantly therewith, the pull-in of the thermostaticelement, may be adjusted.

It will be clear that if the modified sub-assembly shown in Fig. 12 were substituted for that'shown in Figs. 1-5', member 72 could be formed integral with or otherwise non-adjustably xed with respect to supporting means 60.

embodiments and modilications, coacts with the head of the thermostatic sub-assembly to move that. sub-assembly` toward the respective xed contacts rather than by direct engagement of the cam member with the thermostatic element, wear on the thermostatic element is reduced and localized deformation of this element is avoided. Furthermore, by means of the head disposed intermediate the thermostatic element and the cam-providing member movably mounted by the supporting means, the translation of forces from the supporting means to the thermostatic .element is improved since the resultant forces acting on this element are substantially aligned with the path ofV movement thereof.

Obviously, the size, shape and other characteristics of the catch which engages and retainslthe cam carried by the supporting member are limited when they catch is provided by the thermostatic element as in the abovecited patent to J; D. Bolesky since any change in the r size and/ or shapeofthis catch altersl the characteristics of the thermostatic element. In contradistinction thereto, the size and shape of the catch as provided by the abovedescribed intermediate member can be altered as desired to provide optimum shock and vibration resistance as well as other characteristics without modifying or affecting the characteristics of the thermostatic element.

It is noted that it would be a simple matter to modify the shape of the cooperating cams in each of the abovedescribed embodiments and modifications to provide the desired relative type and/or rate of movement of the thermostatic subassembly from the position shown in Figs. or 8 to the position shown in Figs. 2 or 7, respectively. For example, this movement could be relatively slow, relatively rapid or otherwise, as desired.

The environment of the snap-acting element of each of the embodiments set forth in this description may be altered, if desired, by providing the particular embodiment with an auxiliary heater and/ or a slotted, resilient, metallic plate in the manner clearly set forth in Fig. 9 in Figs. l2-15, respectively, of the patent to J.' D. Bolesky referred to above.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings, shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. A device comprising a first electrical contact and a second electrical contact, a snap-acting thermostatic element responsive to temperature change, said thermostatic element carrying said first contact, means biasing said thermostatic element for movement along a path from a first position to a second position with respect to said second contact whereby in said first position the thermostatic element, when it responds to said temperature change, biases said first contact in a direction from engaging to disengaging position with respect to said second contact; said first contact, with said thermostatic element in said second position, being disengaged from said second contact; additional means operatively associated with said thermostatic element for moving said element from said second position to said first position and for retention of said element in said first position until released, said additional means including a member. accessible from the exterior of the device for adjustment of the extent of movement of the thermostatic element from said second position to said first position.

2. A device comprising a first electrical contact and a second electrical contact, a snap-acting thermostatic element responsive to temperature change, said thermostatic element carrying said first contact, means biasing said thermostatic element for movement along a path from a first position to a second position with respect to said second contact whereby in vsaid first position the thermostatic element, when it responds to said temperature change, biases said first contact in a direction from engaging to disengaging position with respect to said second contact; said first contact, with said thermostatic element in said second position, being disengaged from said second contact; additional means operatively associated with said thermostatic element for movement of said element from said second position to said first position and for retention of said element in said first position until released, said additional means including supporting means movable with respect to said thermostatic element and means guided for movement along said path, said supporting means carrying a member in threaded engagement therewith, said last-named means being engageable with said thermostatic element lancl with said member for moving said element along said path from said second position to said first position in response to corresponding movement `of saidk supporting means, and said-member being accessible from the exterior of the device forv said second contact whereby in said first position the thermostatic element, when it responds to said temperature change, biases said first contact in a direction from engaging to disengaging position with respect to said second contact; said first contact, with said thermostatic element in said second position, being disengaged from said second contact; additional meansoperatively associated with'said thermostatic element for movement of said element from said second position to said first position yand forretention of said element in said first position until released, said additional means including a first member movable with respect to said thermostatic element, said additional means further including means guided for movement along said path, said last-named means including a second member threadedly engaging a third member, said third member being engageable with said first member and with said thermostatic element for moving said element along said path from said second position to said first position in response to corresponding movement of said rst member, said third member being accessible from the exterior of the device for adjustment of said third member with respect to said second member to adjust the extent of movement of the thermostatic element from said second position to said first position.

4. A device comprising a first electrical contact and a second electrical contact, snap-acting thermostatic means responsive to temperature change, said thermostatic means carrying said first contact, means biasing said thermostatic means for movement along a path from a first position to a second position with respect to said second contact whereby in said first position the thermostatic means,

when it responds to said temperature change biases said first contact in a direction from engaging to disengaging position with respect to said second contact; said first contact, with said thermostatic means in said second position, being disengaged from said second contact; means guided for movement along said path and engageable with said thermostatic means; said last-named means including a member providing a cam surface and a catch; and additional means movable with respect to said thermostatic means and engageable first with said cam surface for moving said thermostatic means along said path from said second position to said first position and then with said catch for retaining said thermostatic means in said first position until released.

5. A device comprising a base, a first electrical contact, a second electrical contact mounted on said base, a snapacting thermostatic element carrying said first contact and being provided with an aperture extending between opposite sides thereof, said thermostatic element being responsive to temperature change to change its shape, means biasing said thermostatic element from a first position to a second position with respect to said second contact whereby in said first position the thermostatic element, when it responds to said temperature change, biases said first contact in a direction from engaging to disengaging position with respect to said second contact; said first contact, with said thermostatic element in said second position, being disengaged from said second contact; a shank disposed loosely in the aperture in said thermostatic element and having a head fixed with respect thereto, means movable relative to said thermostatic element, said head being engageable with one side of said thermostatic element, saidbiasing means comprising a coil spring coaxial withsaid shank; one end of said spring being engageable with said base, and the other end of said spring abutting said thermostatic element to urge it Vagainst said head, and saidv head providing a surface for cooperation with said last-named means to move said thermostatic element from said second position to said first position and to retain said thermostatic element in said rst position until released.

6. A device comprising a base, a first electrical contact, a second electrical contact mounted on said base, a snap-acting thermostatic element carrying said first contact and being provided with an aperture extending between opposite sides thereof, said thermostatic element being responsive to temperature change, means biasing saidthermostatic element from a first position to a second position with respect to said second contact whereby in said first position the thermostatic element, when it responds to said temperature change, biases said first contact in a direction from engaging to disengaging position with respect to said secondl contact; said first contact, with said thermostatic element in said second position, being disengaged from said second contact; a shank disposed loosely in the aperture in said thermostatic element and having a head fixed with respect thereto, means movable relative to said thermostatic element, said head being engageable with one side of said thermostatic element; a cup-shaped member fixed with respect to said shank at the opposite side of said thermostatic element, said biasing means comprising a spring having one end seated in said cup-shaped member and the other end abutting said base member, and said head providing a surface for cooperation with said relatively movable means to move said thermostatic element from said second position to said first position.

7. A device comprising a base, a first electrical contact, a second electrical contact mounted on said base, snap-acting thermostatic means carrying said first contact and being responsive to temperature change to change its shape, spring means engageable with said base and biasing said thermostatic means for movement fromI a first position to a second position with respect to said second contact whereby in said first position the thermostatic means when it responds to said temperature change, biases said first contact in a direction from engaging to disengaging position with respect to said second contact; said rst contact, with said thermostatic means in said second position, being disengaged from said second contact; supporting means mounted on said base for movement with respect to said thermostatic means, a member carried by said supporting means and providingv a rst cam surface; means including two portions fixed with respect to each other, one of said portions being adapted to abut said thermostatic means, the other of said portions presenting a second cam surface for cooperation with said first cam surface whereby said thermostatic means is moved from said second position to said first position in response tomovement of said supporting means, said last-named means providing a catch adjacent said second cam. surface for retaining said 'member to maintainV said thermostatic means in said first position until said member isv forcibly retracted or until siad thermostatic means responds to said temperature change; andv means engageable with said base and biasing said supporting means for movement of said member to retracted position when said thermostatic means responds to said temper-l ature change.

8. A device comprising a base, a first electrical contact, a second electrical contact mounted on said base, snap-acting thermostatic means carrying said first contact and being responsive to temperature change to change its shape, spring means engageable with said base and biasing said thermostatic means for movement from a first position to a second position with respect to said second Contact whereby in saidv first position the thermostatic means when it responds to said temperature change, biases said first contact in a direction from engagingy to disengaging position with respect to said second'contact; said first contact, with said thermostatic means in said second position, being disengaged from said second Contact; supporting means mounted on said base for movement with respect to said thermostatic means, a member carried by said supporting means and providing a first cam surface; means including two portions fixed with respect to each other, one of said portions being adapted to abut said thermostatic means, the other of said portions presenting a second cam surface for cooperation with said first camsurface whereby said thermostatic means is moved from said second position to said first position in response to movement of said supporting means, said last-named means providing a catch adjacent said second cam surface for retaining said member to maintain said thermostatic means in said first position until said member is forcibly retracted or until said thermostatic means responds to said temperature change; and means engageable withy said base and biasing said supporting means for movement of said member to retracted position when said thermostatic means responds to said temperature change, said member threadedly engaging said supporting means and said member being accessible from the exterior of the device for adjustment of said member 'al-ong said supporting means.

9. A device comprising a base, a first electrical contact, a second electrical contact mounted on said base,

snap-acting thermostatic means carrying said first contact and being responsive to temperature change to change its shape, spring means engageable with said base camsurface; means including two portions fixed with respect to each other, one of said portions being adapted to abut said thermostatic means, the other of saidl portions presenting a second cam surface for cooperation with said first cam surface whereby said thermostatic means is moved from said second position to said first position in response to movement of said supporting means, said last-named means providing a catch adjacent said second cam surface for retaining said member tomaintain said thermostatic means in said first positionuntil said member is forcibly retracted or until said. thermostatic means responds to said temperature change;`

and means engageable with said base and biasing said supporting means for movement of said member to retracted position when said thermostatic means respondsv to said temperature change, said other portion being being adjustably fixed in threaded engagement with said one portion and being accessible from the exterior of the device for adjustment thereof with respect to said one portion.

l0. A device comprisingV a base, a 'first electrical contact, a second electrical contact mounted on said base, snap-acting thermostatic means carrying said first contact and being responsive to temperature change, springv means engageable with said base and biasing said thermostatic means for movement from a first position to a second position with respect to said second contact whereby in` said first position the thermostatic means, whenk it responds to said temperature change, biases said firstV contact in a direction'from engaging to disengaging position with respect to said second contact; said first contact, with said thermostatic means in said second position, being disengaged from said second contact; supporting means mounted on said base for pivotal movement about an axis, a member carried by said supporting means and having a rst cam surface at one end; means including two portions fixed with respect to each other, one of said portions being adapted to abut said thermostatic means, the other of said portions presenting a second cam surface for cooperation with said first cam surface whereby said thermostatic means is moved from said second position to said tirst position in response to pivotal movement of said supporting means, said last-named means providing a catch adjacent said second cam surface for retaining said member to maintain said thermostatic means in said first position until said member is forcibly retracted or until said thermostatic means responds to said temperature change; and means engageable with said base and biasing said supporting means for pivotal movement of said member to retracted position when said thermostatic means responds to said temperature change.

11. A device comprising a base, a first electrical contact, a second electrical contact mounted on said base, snap-acting thermostatic means carrying said first contact and being responsive to temperature change, spring means engageable with said base and biasing said thermostatic means for movement from a first position to a second position with respect to said second contact whereby in said iirst position thermostatic means, when it responds to said temperature change, biases said first contact in a direction from engaging to disengaging position with respect to said second contact; said first contact, with said thermostatic means in said second position, being disengaged from said second contact; supporting means slidably mounted on said base for rectilinear movement along a path lying transversely with respect to the path of movement of said thermostatic means between said lirst and second positions, a member carried by said supporting means and having a first cam surface at one end, means including two portions iixed with respect to each other, one of said portions being adapted to abut said thermostatic means, the other of said portions presenting a second cam surface for cooperation with said first cam surface whereby said thermostatic means is moved from said second position to said first position in response to rectilinear movement of said supporting means, said last-named means providing a catch adjacent said second cam surface for retaining said member to maintain said thermostatic means in said first position until said member is forcibly retracted or until said thermostatic means responds to said temperature change; and means engageable with said base and biasing said supporting means for rectilinear movement of said member to retracted position when said thermostatic means responds to said temperature change.

12. The device las set forth in claim 2 wherein said member provides a socket and includes a rotatable spherical ball retained within said socket whereby said ball comprises the portion of said member engageable with said last-named means.

References Cited in the le of this patent UNITED STATES PATENTS 1,767,709 Smith June 24, 1930 2,032,136 Lee Feb. 25, 1936 2,293,179 Swingle Aug. 18, 1942 2,300,530 Swingle Nov. 3, 1942 2,345,451 Bolesky Mar. 28, 1944 2,371,672 Bolesky Mar. 20, 1945 2,467,745 Harrison Apr. 19, 1949 2,617,909 Cataldo et al. Nov. 11, 1952 2,757,256 Cataldo et al. July 31, 1956 Umts smits Mimi @FFME CERTIFECATEEL @F CORlPECTON Patent No., 2986,3965 December 9, 1958 t It is hereby certified that error appears in'V the -prnted specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Golunm 2, line 24, foird "drawings" read m drawing ms; column 3, lines 2l and, for "relative" read m relatively m-g column 6, line 3, "ooopeiating" Tread Cooperation cm; column lly line 62, for "sied" 'feed m said am; Column l, line 29, after "position" insert the mo Signed and sealed this 2 th day of April lffj.,

(SEAL) Attest:

KARL Ha .A INE ROBERT C. WATSON Commissioner of Patents Attesting Officer Umts@ s'mss ammi esmas QCEHHCATE'L @F @@RECNGN Pa tent Nol 635,965 December 99 1958 x Wlfre Wo GafL et alo It is henc'ebr certified that error appears in theprnted specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 9 line 249 f "olf "dzaawngef' read m drawing me; Column 3, linee 2l and. 222? for "ye-lative" Zweed m relatively uw; Column 6, line 3, eooperatmy read Cooperation m; @011mm lly line' @2y ol'u "sad" um said we; column 13, line 29, after "position" insert n the ma Signed and sealed this 26th Clay of Apll lffjo (SEAL) Attest:

KARL He ,XLINE ROBERT C. WATSON Commissioner of Patents ttestng Ufficer 

